Im am just getting started on porting a mixer from windows to linux. It is sort of working.
I am testing with pulseaudio on a laptop. Using the built in mic amd the speakers is starts fine. But after a few minutes it gets real distorted and delayed about 1/2 second. When first started the letancy was barely noticablewith no distortion.
On windows using asio drives I never saw anything like this.
Does this behavior ring any bells with anyone?
Mark
Sorry, I'm confused. Is this a general question - or a JUCE one?
If general, I'd say something was accumulating. An error value or, may be the dreaded floating point "pentium" bug (oft encountered in DSP forums, but I can't say I've heard of it for a while)
Can you explain what you're doing - e.g. Running juce's Host and connecting inputs to outputs (and nothing else)?
Not a general question, a juce question. Thee mixer application is built using juce device manager. I am juce learning how linux audio works, very different from windoze. I have pulseaudio running with alsa input, jack is not running. Input is routed to from the built in mic to the mixer and output routed to the speakers. starts out fine deteriorates after a while. Is I stop and start the mixer(remove and readd the audiocallback) the problem is not resolved. I need to stop and start the program to get it working again.
My guess is that if this was a general problem, we'd have heard about it before, so it's more likely to be something you're doing in your app.. Perhaps leaking? Or some dodgy threading code that's deadlocking?
Thanks for the reply. I was not implying it is a Juce problem. I was just hoping some would have made the same mistake I have and know what I am doing wrong.
This might have been more appropriate in the Linux platform forum though I don't know for sure it is specific to linux.
I could be a juce problem, but is very hard to tell from what you've said, and nothing springs to mind.. Keep us posted with any other clues.
Jules, you're not a problem for JUCE ;)
I'm definitely its biggest problem!
I finally got the problem solved. I was having so much trouble getting audio to work correctly with jack/asla/pulse... that I started over. I reinstalled kxstudio, erasing the harddrive and it looks like all my audio problems cleared up.
So you are not the problem after all Jules. 
But now I have a juce-jack question. I start my mixer application, and in the audio settings I select jack and system for for input and output the click the channels to use. (There are 18 in and 20 out to choose from) This works and my mixer gets input and output from my usb device. But what I see in the catia (jack routing) window has me confused.
2 devices get added, JuceJack that has 18 in/20 out. This matches the scarlett 18i20 interface for number of i/o. But why? The mixer can have more or less inputs than that so how do the number of channels get set for the jucejack device?
The second device is JackJuce-1 and it has 5 sets of 18 inputs and 5 sets of 20 outputs, but has the same number of inputs automatically routed as JuceJack. I don't understand why there are 2 JuceJack devices and why does the second one have 5 times as many ins and outs?
Mark.